Segmental abrasive wheel



July 5, 1932. a. N. JEPPSON ETAL 1,865,523

v SEGIB NTAL ABRASIVE WHEEL Filed April 2, 1928 I Inventors Wltnesses fieolyeflfippsv l M I Ifiare [arsson W -W Patented 193:2

- grains bonded by vitrifie UNITED, STATES PATENT OFFICE GEORGE N. JEPPSON AND THUBE LABSSON, OF WORCESTER, I ASSLCHUSMTS, AS-

SIGN'OBS '1O NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION or nassacnusn'r'rs smmrar. nmslvn wmn and more particularl to a segmental grinding wheel in which t e segments of abrasive ceramic material are mounted upon a rotary su port.

It has been pro osed hereto ore to make a large sized grinding wheel of abrasive segments mounted on a metal drum for use in grinding wood pulp and the like. Such a segmental whee is however expensive to manufacture, partly because of the size and weight of the drum but more because of the difliculties involved in mounting the segments on the drum. A wheel used for grin ing wood pulp is subjected to enormous forces from without, owin to the fact that the logs of wood are presse against the wheel under hydraulic pressure, as well as lar e internal stresses resultin from the centri ugal force set up by rotating the wheel at high speed and because of ex ansion and contraction of the wheel under te changes of temperature required for grinding ence of hot water. t has heretofore een advisable, in order to mount the segments rigidl and securely on the metal drum, to provi e each segment with a metal shoe and to have the surface of the drum carefully ground to a smooth and accurate shape in order that the shoes of the segment may fit correctly thereon.

The rimary object of this invention is to avoid t e necessity of using a massive iron drum which must be accurately finished and shaped to fit the segments and which must be sufliciently rigid and strong to hold them under the enormous strains of the grinding operation, and particularly to provide a simple, inexpensive type of segmental grinding wheel which may be readily manufactured and assembled and which will serve efliciently for grinding wood pulp as well as various other types of material.

A further object of the invention is to provide a unitary type of grinding wheel made up of abrasivesegments mounted rigidly in position onv a central support, and particularly one in which the central supporting body is formed as a monolithic structure the pulp in the reselevation showing the abrasive segments,

266,481, and in Canada October 4, 1928.

which is substantially integral with the segments.

To the accomplishment of these objects and such others as will be apparent to one skilled 1n the art, we propose to utilize a concrete or other monolit ic structure as the supprting 'body for a plurality of abrasive segments arran ed on the surface thereof,'and in order that t e segments may be safely held in p0- sltion under the enormous stresses of a rinding operation, we employ clamping locks enga 'ng the abrasive segments tohol them rigid y in position. F

One embodiment of this invention is shown in the accompanyin drawing, in 'which:,

Fig. 1 is a perspective of the grindin wheel with severa segments removed to show the su porting concrete body, as well as the adhustable clamping blocks which secure the segments to the body;

Fig. 2 is a fragmentary detail in sectional clamping blocks and the adjustable bolts embedded in the concrete and securing the segments in position; a

Fig. 3 1s a sectional elevation on the line Fig. 4 is an enlarged sectional elevation similar to Fig. 3, but taken on a different line on Fig. 2, showing the reinforcin members which straighten the concrete b0 y; and

Fig. 5 is a fragmentary detail in sectional elevation showing, enlarged, the abrasive segments in their assembled position.

The embodiment of our invention illustrated in the drawing comprises a plurality of segments 6, composed of abrasive grains bonded by suitable material, such as vitrified ceramic material, which are mounted with their side faces 7 spaced apart to form an of the wedge-shaped a rasive sultably secured to the concrete bod and The clamping blocks 12, in the form illustrated comprise wedge shaped heads formed on the outer ends of rectangular webs 13. These webs may rest on strips of elastic material 15, such as rubber or other resilient material, suitabl placed between the bottoms of the webs and the ribs 11 to prevent the concrete from flowing around the webs when the central body is cast, and yet provide a pad of sufficient s ringiness to permit the ti htening of the c amping blocks.

ach segment, at the lower portions of the reentrant shoulders 16, is provided with an inner facing shoe 17 of lead cast integrally thereon and bonded intimately with the porous surface of the segment. These shoes 17, which extend the full width of the segments, have a fitting engagement with the lower portions of the blocks 6 (Fig. 5). The interstices between the adjacent faces 7 of the segments are filled with a suitable cementi t-ious filler 19, such as lead, which is poured in a molten state so that the heads 12 become completely covered (Fig. 5).

Each clamping block 12 is connected to a mandrel 21 within the concrete cylinder 10 by a plurality of bolts 20, which are incased in the concrete. The upper ends of the bolts 20 are threaded into the webs 13 while the lower ends of the bolts passloosely through the mandrel 21. The bolts 20, which may be somewhat elastic under tension, have 'nuts 22 and washers 23 thereon, serving to secure the bolts to the mandrel 21, a locking nut 24. being used to prevent the parts from becomin loosened.

he concrete cylinder 10 is preferably reinforced. To this end numerous concentric circular hoops 25 are arranged as shown in Figs. 2, 3 and 4. A plurality of cross rods 26 are connected to the peripheries of the hoops .25 by a twisted wire tie 27 which is wrapped around the hoops and rods at each point of contact. The two concentric rows of hoops are also connected by wires 28 which have their respective ends twisted about the hoops.

To construct the grinding wheel, the reinforcing net-work composed of the hoops 25, the rods 26 and wires 28, is formed loosely around the mandrel 21. The clamping blocks are then threaded upon the upper ends of the bolts 20, the lower ends of which are inserted through the holes in the mandrel and then provided with the washer 23, the nut 22 and the nut 24. The nuts 22 and 24 are adjusted to allow the clamping blocks to be withdrawn and positioned from the mandrel the proper distance in which they may be braced by temporary wooden braces or by sleeves of metal or other material surrounding the bolts, and which may form a permanent part of the wheel structure.

After the clamping blocks are braced out- 5 wardly from the mandrel, the-wedge shaped abrasive segments are slipped sidewise between the pairs of blocks 12, and they interlock with the reentrant shoulders 16 and engage the lead facing shoes 17. After the various segments have been placed in position, the crevices between the segments are then wedged to hold the grinding surfaces thereon in the proper relative relation. This may necessitate adjustment of the position of the blocks 12 through manipulation of the nuts 22 and 24.

When the segments are all assembled in position and wedged apart to form the proper cylindrical grinding surface they are bound with wire so that they may be up-ended upon a circular form forming a base upon which to pour the concrete. The temporary braces, if they were used, are removed and the bolts 20, between the mandrel and the webs 13 are provided with sleeves of heavy grease. The concrete is now poured into the space between the mandrel and the segments. During this operation the reinforcing net-work may be held in its proper central position without difficulty. The fluid concrete flows into engagement with the bottom faces of the segments and fills the interstices between the packings 15 beneath the clamping blocks and the side faces 7 of the segments, thus forming the ribs 11 on the con crete cylinder 10. The concrete makes an intimate bond with the porous surface of the segments.

After the concrete has set, the wires binding the segments together and the wedges between the adjacent faces of the segment are removed. The nuts 22 are now sufliciently tightened so that the greased bolts 20 pull the heads 12 of the clamping blocks against the facing shoes 17, tightly squeeze the elastic strips 15 between the web bottoms and the ribs 11, and draw the segments down into' firm contact with the surface of the concrete cylinder 10. This tightening process places the elastic bolts under longitudinal tension. The bolts thus permit expansion of the wheel under heat, and contraction of the wheel upon cooling. After this operation the lead filler 19 is poured into the crevicesthe described and illustrated embodiment of the invention being intended as an exploitation of its underlying essentials, the'features whereof will be definitely stated in their true scope in the claims hereto appended. It will also be understood that one may construct a wheel, by this method, which grinds on one plane end face, and that various other shapes as well as sizes of wheel may be thus made. It will also be understood that we may utilize in place of concrete various types of fluid material capable of being poured or molded in situ and of setting to a hard condition, and forming a support for the abrasive blocks.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. That improvement in the art of making grindin wheels which consists in arranging a plura ity of abrasive segments independently of their final support in such a position as to form a grinding surface, then forming the internal supporting structure for all the segments in situ and thereafter adjustably forcing the segments radially inwardly into position on said structure.

2. That improvement in the art of making rinding wheels which consists in connecting oosely a plurality of clamping blocks to a mandrel, arranging a plurality of abrasive segments between and in operative relation to said blocks and spaced from said mandrel to form a grinding surface, filling the interstices between the mandrel and the segments with a fluid material capable of solidifying and forming a support for the segments, causing said material to harden and thereafter adjustably drawing the clamping blocks towards the mandrel and thereby fixing the segments rigidly in position on the support.

3. That improvement in the art of making rinding wheels which consists in building ooselyv around a mandrel a reinforcing network,connecting loosely a plurality of clamping blocks to the mandrel, arranging a plurality of abrasive segments between said blocks in a position spaced from the net-work to form a cylindrical grinding surface, and then filling the interstices between the mandrel and the segments with a fluid material capable of solidifying and forming a support for the segments.

4. That improvement in the art of making grinding wheels which consists in arranging a. plurality of porous segments of abrasive grains bonded by vitrified ceramic material independently of one another and their final support in such a position as to form a grinding surface, embedding the lower portions of said segments in a fluid material capable of solidifying in an intimate bonded relation with the porous surfaces of all the embedded segments and forming a support therefor, and thereafter forcing the segments radially inwardly into a firm position on said support.

5. That improvement in the art of making grinding wheels which consists in bolting loosely a plurality of clamping blocks to a mandrel, arranging a plurality of abrasive segments between said blocks in a position spaced from said mandrel to form a cylindrical grinding surface, filling the interstices A between the mandrel and the segments with a fluid material capable of solidifying to form a support for the segments and then connecting the blocks to the mandrel with elastic ten- S1011.

.6. The method of making a grinding wheel comprising the steps of assembling a set of abrasive segments in a spaced annular arrangement independently of their final support so as to form agrinding surface, casting a body of solidifiable material within the an nulus and in intimate contact with the bottom faces of the abrasive segments so as to form a supporting seat therefor, then after said body has solidified forcing the segments radially inwardly into firm contact therewith, and filling the crevices between the segments.

7. A grinding wheel comprising a plurality of abrasive segments arrangedas an annulus, a rotary support of material molded in situ which contacts with and fits intimately against the adjacent surfaces of the segments, and adjustable means for drawing the segments radially inwardly and securing them rigidly in position on the support.

8. A grinding wheel comprising a plurality of abrasive segments arranged as an annulus, a support therefor having its surface molded against and forming a supporting seat for the inner faces of the segments and means, including adjustable clamping members secured to the support and cooperating shoulders on the segments, for forcing the segments radially inwardly and securing them in firm contact with the support.

9. A grinding wheel comprising a plurality of abrasive segments arranged in spaced relation as an annulus, a body of cement within and forming substantially the sole support for the annulus, the outer surface of which fits intimately against the irregular surface of each abrasive segment, adjustable means for forcing the segments radially inwardly into firm contact with said body, and a filler in the interstices between adjacent faces of the segments.

10. A grinding wheel comprising a plurality of abrasive segments arranged in spaced relation as an abrasive annulus, a supporting body molded in position against and intimately fitting the inner surfaces of said abrasive segments, said body forming substantially the sole support for the segments, ad- 1 justable means to force the segments radially inwardly into position on the supporting body, and a filler in the interstices between adjacent faces of the segments.

11. A grinding wheel comprising a cylindrical body having a plurality of channels formed laterally therein, a plurality of abrasive'segments seated in said channels, a plurality of clamping blocks, each being located between and engaging the sides of adjacent segments, said blocks and se cooperating interlocking sur aces, and adiusdta'ble means for securing each block to said 12. A grindingwheel comprisinga cylindrical body having a plurality of channels formed laterally therein, a plurality of abrasive segments seated in said channels, each segment having reentrant shoulders formed on its opposite side faces and facing shoes I ments, said blocks and segments having cooperating, interlocking surfaces and bolts secured to the concrete cylinder and connecting each block and the mandrel.

14. A grinding'wheel comprising a central mandrel, a reinforced concrete cylinder encasing the mandrel, a plurality of abrasive segments on the surface of said cylinder, a

plurality of clamping blocks between the segments, said blocks and segments having co- 39 operating interlocking surfaces, bolts connecting each block with the mandrel which are arranged to move freely through the concrete, and a filler in the interstices between adjacent faces of the segments.

15. A grinding wheel comprising a mandrel, a series of abrasive segments surrounding but spaced from the mandrel and forming a grinding surface, clamping blocks adjustably secured to the mandrel and the segments to hold the latter against outward movement, and a filling of concrete between the mandrel and the segments which serves as the support for the segments.

16. A grinding wheel comprising a mandrel, a series of abrasive segments arranged around but spaced at a considerable distance from the mandrel to form a grinding surface, the segments haw'ng clamping shoulders thereon, blocks engaging said clamping shoulders, adjustable means for forcing the blocks inwardly towards the mandrel, a cementitious filler between the segments, and a rigid molded body between the mandrel and segments having intimate contact with the segments and serving substantially as the sole support therefor.

17. A grinding wheel comprising a series of abrasive segments arranged as an annulus and provided with clamping shoulders, clamping blocks engaging said shoulders, a molded body within the abrasive annulus which contacts directly with and forms a support for the segments and adjustable means including adjustable members embedded in said body to force the segments radially inents having wardly' and secure them port.

of abrasive segments in an annular arrangement which have clamping shoulders thereon, clamping blocks engaging said shoulders,

' a molded body in the space within the annulus which makes intimate contact with the segments and forms a rigid'and substantially the sole support for the same, adjustable members movable within sai'dbody and engaging the blocks and means associated therewith permitting said members to be drawn inwardly to clamp the blocks tightly against the body. Y

19(A grinding wheel comprising a body of molded concrete having ribs thereon, a series of abrasive segments mounted on said body and having clamping shoulders and portions between the ribs to prevent circumferential displacement, clamping-blocks engaging said shoulders, tie rods connected with the blocks and movably embedded in the concrete, and means for adjusting said rods to secure the segments rigidly in position.

20. A grinding wheel comprising a massive body of concrete forming a support, abrasive. segmens mounted on said support and forming a grinding surface, clamping members engaging the segments and ad ustable means associated therewith which serve to draw the segments radially inwardly into a rigid relationship to the support.

Signed at Worcester, Massachusetts, this 29th day of March, 1928.

THURE LARSSON. GEORGE N. )EPPSON.

18. A grinding wheel com prising a series I rigidly on said sup- 

